Cross-platform replication

ABSTRACT

One or more techniques and/or computing devices are provided for cross-platform replication. For example, a replication relationship may be established between a first storage endpoint and a second storage endpoint, where at least one of the storage endpoints, such as the first storage endpoint, lacks or has incompatible functionality to perform and manage replication because the storage endpoints have different storage platforms that store data differently, use different control operations and interfaces, etc. Accordingly, replication destination workflow, replication source workflow, and/or a proxy representing the first storage endpoint may be implemented at the second storage endpoint comprising the replication functionality. In this way, replication, such as snapshot replication, may be implemented between the storage endpoints by the second storage endpoint using the replication destination workflow, the replication source workflow, and/or the proxy that either locally executes tasks or routes tasks to the first storage endpoint such as for data access.

RELATED APPLICATIONS

This application claims priority to and is a continuation of U.S.application Ser. No. 15/995,607, filed on Jun. 1, 2018, now allowed,titled “CROSS-PLATFORM REPLICATION,” which claims priority to and is acontinuation of U.S. Pat. No. 9,990,260, filed on Apr. 29, 2016 andtitled “CROSS-PLATFORM REPLICATION,” which are incorporated herein byreference.

BACKGROUND

Many storage networks may implement data replication and/or otherredundancy data access techniques for data loss protection andnon-disruptive client access. For example, a first storage cluster maycomprise a first storage controller configured to provide clients withprimary access to data stored within a first storage device and/or otherstorage devices. A second storage cluster may comprise a second storagecontroller configured to provide clients with primary access to datastored within a second storage device and/or other storage devices. Thefirst storage controller and the second storage controller may beconfigured according to a disaster recovery relationship, such that thesecond storage controller may provide failover access to replicated datathat was replicated from the first storage device to a secondary storagedevice, owned by the first storage controller, but accessible to thesecond storage controller (e.g., a switchover operation may be performedwhere the second storage controller assumes ownership of the secondarystorage device and/or other storage devices previously owned by thefirst storage controller so that the second storage controller mayprovide clients with failover access to replicated data within suchstorage devices). In an example of a logical replication scheme, thesecond storage controller has ownership of the replicated data. Thesecond storage controller may provide read-only access to the replicateddata. The second storage controller may convert the replicated data tofull read-write access upon failover. In an example of physicalreplication, the storage device, comprising the replicated data, isowned by the first storage controller until a failover/switchover to thesecond storage controller occurs.

In an example, the second storage cluster may be located at a remotesite to the first storage cluster (e.g., storage clusters may be locatedin different buildings, cities, thousands of kilometers from oneanother, etc.). Thus, if a disaster occurs at a site of a storagecluster, then a surviving storage cluster may remain unaffected by thedisaster (e.g., a power outage of a building hosting the first storagecluster may not affect a second building hosting the second storagecluster in a different city).

In an example, two storage controllers within a storage cluster may beconfigured according to a high availability configuration, such as wherethe two storage controllers are locally connected to one another and/orto the same storage devices. In this way, when a storage controllerfails, then a high availability partner storage controller can quicklytakeover for the failed storage controller due to the localconnectivity. Thus, the high availability partner storage controller mayprovide clients with access to data previously accessible through thefailed storage controller.

In an example of a high availability configuration, high availability todata may be provided without using shared storage. In particular, highavailability to data can be provided using a synchronous replicated copyof a primary storage object. The high availability to data may beprovided through a software defined architecture, using synchronousreplication, and is not limited to merely two storage controllers.

Various replication and synchronization techniques may be used toreplicate data (e.g., client data), configuration data (e.g., a size ofa volume, a name of a volume, logical unit number (LUN) configurationdata, etc.), and/or write caching data (e.g., cached write operationsnot yet flushed to a storage device, but cached within memory such as anon-volatile random access memory (NVRAM)) between storage controllersand/or storage devices. Synchronous replication may be used where anincoming write operation to the first storage controller is locallyimplemented upon a first storage object (e.g., a file, a LUN, a LUNspanning multiple volumes, or any other type of object) by the firststorage controller and remotely implemented upon a second storage object(e.g., maintained as a fully synchronized copy of the first storageobject) by the second storage controller before an acknowledgement isprovided back to a client that sent the incoming write operation. Inanother example, asynchronous replication may be achieved by capturingsnapshots of a volume, determining data differences (e.g., deltas)between a current snapshot and a last snapshot used to replicate data tothe second storage object, and using incremental transfers to send thedata differences to the second storage controller for implementationupon the second storage object. Semi-synchronous replication may beachieved where an acknowledgment back to a client for a write request isbased upon local implementation upon the first storage object, but isnot dependent upon remote implementation upon the second storage object.

A storage environment may comprise storage controllers with differentstorage platforms. For example, the storage environment may havedifferent versions or models of storage controllers (e.g., a storagecontroller with a disk based storage platform, a flash array storageplatform, a volume based storage platform, a consistency group of filesand/or LUNs storage platform, a distributed storage platform such ascloud storage, etc.) that store data differently, use different extentsizes, have different compression characteristics, support differenttypes of storage operations and syntax, have different data and controlinterfaces, provide different user interfaces for administrators, etc.Unfortunately, cross-platform storage controllers with different storageplatforms may be unable to establish and facilitate data replication andother functionality with one another. Thus, data replication andprotection may be unavailable for cross-platform storage controllers.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a component block diagram illustrating an example clusterednetwork in accordance with one or more of the provisions set forthherein.

FIG. 2 is a component block diagram illustrating an example data storagesystem in accordance with one or more of the provisions set forthherein.

FIG. 3 is a flow chart illustrating an exemplary method ofcross-platform replication.

FIG. 4A is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where a proxy is implemented at afirst storage endpoint.

FIG. 4B is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where replication source workflowand replication destination workflow are implemented at a first storageendpoint.

FIG. 4C is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where replication source workflowand replication destination workflow are implemented at a first storageendpoint.

FIG. 4D is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where data transfer is performedbetween a first storage endpoint and a second storage endpoint.

FIG. 5 is a flow chart illustrating an exemplary method ofcross-platform replication.

FIG. 6A is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where a proxy is implemented at asecond storage endpoint.

FIG. 6B is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where replication source workflowand replication destination workflow are implemented at a second storageendpoint.

FIG. 6C is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where replication source workflowand replication destination workflow are implemented at a second storageendpoint.

FIG. 6D is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where data transfer is performedbetween a first storage endpoint and a second storage endpoint.

FIG. 7 is a flow chart illustrating an exemplary method ofcross-platform replication.

FIG. 8A is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where a proxy is implemented at astorage server.

FIG. 8B is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where replication source workflowand replication destination workflow are implemented at a storageserver.

FIG. 8C is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where replication source workflowand replication destination workflow are implemented at a storageserver.

FIG. 8D is a component block diagram illustrating an exemplary computingdevice for cross-platform replication, where data transfer is performedbetween a first storage endpoint and a second storage endpoint.

FIG. 9 is an example of a computer readable medium in accordance withone or more of the provisions set forth herein.

DETAILED DESCRIPTION

Some examples of the claimed subject matter are now described withreference to the drawings, where like reference numerals are generallyused to refer to like elements throughout. In the following description,for purposes of explanation, numerous specific details are set forth inorder to provide an understanding of the claimed subject matter. It maybe evident, however, that the claimed subject matter may be practicedwithout these specific details. Nothing in this detailed description isadmitted as prior art.

One or more techniques and/or computing devices for cross-platformreplication are provided herein. For example, a first storage endpoint(e.g., a source storage controller hosting source storage) and a secondstorage endpoint (e.g., a destination storage controller hostingdestination storage into which data from the source storage is to bereplicated) may have different storage platforms (e.g., a disk basedstorage platform, a flash array storage platform, a volume based storageplatform, a consistency group of files and/or LUNs storage platform, adistributed storage platform such as cloud storage, etc.) that do notnatively support replication between one another.

Accordingly, as provided herein, a replication relationship may beestablished and managed using replication source workflow andreplication destination workflow (e.g., control operations, a get volumeinformation operation, a create snapshot operation, a create streamoperation, a manage stream operation, a set tag operation, a determinedifferences between two snapshots operation, a data transfer managementoperation, etc.) executing on a single device (e.g., executing on thefirst storage endpoint, the second storage endpoint, or a separatestorage server). A proxy is used to represent a storage endpoint (e.g.,represent storage hosted by the storage endpoint, such as a destinationvolume) at which the replication source workflow and the replicationdestination workflow are not executing because the storage endpoint maynot natively support replication facilitated by the other storageendpoint. For example, if the replication source workflow and thereplication destination workflow are executing at the first storageendpoint, then a proxy, representing the second storage endpoint (e.g.,representing second storage of the second storage endpoint), may behosted at the first storage endpoint. In an example, the first storageendpoint, but not the second storage endpoint, may comprisefunctionality to perform replication such as snapshot replication, andthus the replication source workflow, the replication destinationworkflow, and the proxy are hosted at the first storage endpoint.

When the proxy is hosted at the first storage endpoint, certaindestination workflow tasks associated with snapshot replication may beexecuted upon the proxy (e.g., executed against a physical or virtualproxy volume used to represent destination storage such as the secondstorage of the second storage endpoint) because the proxy is compatiblewith snapshot replication (e.g., control operations, such as a createstream operation that does not require data from a file system of thesecond storage, may be locally executed upon the proxy). Otherdestination workflow tasks associated with snapshot replication may beimplemented upon the proxy and routed by the proxy to the second storage(e.g., a file system access operation, which may use actual data withinthe second storage, may be routed to the second storage for retrieval ofsuch data). In this way, a replication operation may be performed toreplicate data from the first storage of the first storage endpoint tothe second storage of the second storage endpoint (e.g., a baselinetransfer of a volume or consistency group of files and/or logical unitnumbers (LUNs), an incremental transfer of a delta between a currentsnapshot of the first storage and a last snapshot of the first storageused to transfer data to the second storage, etc.). Because thereplication source workflow, the replication destination workflow, andthe proxy are hosted at the first storage endpoint (e.g., the firststorage endpoint is capable of managing data transfer, controloperations, the replication relationship, a state machine, etc.), thesecond storage endpoint may be a lightweight endpoint that does not needfunctionality to fully support all aspects of snapshot replication(e.g., the second storage endpoint may have send and/or receivefunctionality for actual data replication, while other aspects ofsnapshot replication are handled by the proxy).

To provide cross-platform replication, FIG. 1 illustrates an embodimentof a clustered network environment 100 or a network storage environment.It may be appreciated, however, that the techniques, etc. describedherein may be implemented within the clustered network environment 100,a non-cluster network environment, and/or a variety of other computingenvironments, such as a desktop computing environment. That is, theinstant disclosure, including the scope of the appended claims, is notmeant to be limited to the examples provided herein. It will beappreciated that where the same or similar components, elements,features, items, modules, etc. are illustrated in later figures but werepreviously discussed with regard to prior figures, that a similar (e.g.,redundant) discussion of the same may be omitted when describing thesubsequent figures (e.g., for purposes of simplicity and ease ofunderstanding).

FIG. 1 is a block diagram illustrating the clustered network environment100 that may implement at least some embodiments of the techniquesand/or systems described herein. The clustered network environment 100comprises data storage systems 102 and 104 that are coupled over acluster fabric 106, such as a computing network embodied as a privateInfiniband, Fibre Channel (FC), or Ethernet network facilitatingcommunication between the data storage systems 102 and 104 (and one ormore modules, component, etc. therein, such as, nodes 116 and 118, forexample). It will be appreciated that while two data storage systems 102and 104 and two nodes 116 and 118 are illustrated in FIG. 1, that anysuitable number of such components is contemplated. In an example, nodes116, 118 comprise storage controllers (e.g., node 116 may comprise aprimary or local storage controller and node 118 may comprise asecondary or remote storage controller) that provide client devices,such as host devices 108, 110, with access to data stored within datastorage devices 128, 130. Similarly, unless specifically providedotherwise herein, the same is true for other modules, elements,features, items, etc. referenced herein and/or illustrated in theaccompanying drawings. That is, a particular number of components,modules, elements, features, items, etc. disclosed herein is not meantto be interpreted in a limiting manner.

It will be further appreciated that clustered networks are not limitedto any particular geographic areas and can be clustered locally and/orremotely. Thus, in one embodiment a clustered network can be distributedover a plurality of storage systems and/or nodes located in a pluralityof geographic locations; while in another embodiment a clustered networkcan include data storage systems (e.g., 102, 104) residing in a samegeographic location (e.g., in a single onsite rack of data storagedevices).

In the illustrated example, one or more host devices 108, 110 which maycomprise, for example, client devices, personal computers (PCs),computing devices used for storage (e.g., storage servers), and othercomputers or peripheral devices (e.g., printers), are coupled to therespective data storage systems 102, 104 by storage network connections112, 114. Network connection may comprise a local area network (LAN) orwide area network (WAN), for example, that utilizes Network AttachedStorage (NAS) protocols, such as a Common Internet File System (CIFS)protocol or a Network File System (NFS) protocol to exchange datapackets, a Storage Area Network (SAN) protocol, such as Small ComputerSystem Interface (SCSI) or Fiber Channel Protocol (FCP), an objectprotocol, such as S3, etc. Illustratively, the host devices 108, 110 maybe general-purpose computers running applications, and may interact withthe data storage systems 102, 104 using a client/server model forexchange of information. That is, the host device may request data fromthe data storage system (e.g., data on a storage device managed by anetwork storage control configured to process I/O commands issued by thehost device for the storage device), and the data storage system mayreturn results of the request to the host device via one or more storagenetwork connections 112, 114.

The nodes 116, 118 on clustered data storage systems 102, 104 cancomprise network or host nodes that are interconnected as a cluster toprovide data storage and management services, such as to an enterprisehaving remote locations, cloud storage (e.g., a storage endpoint may bestored within a data cloud), etc., for example. Such a node in theclustered network environment 100 can be a device attached to thenetwork as a connection point, redistribution point or communicationendpoint, for example. A node may be capable of sending, receiving,and/or forwarding information over a network communications channel, andcould comprise any device that meets any or all of these criteria. Oneexample of a node may be a data storage and management server attachedto a network, where the server can comprise a general purpose computeror a computing device particularly configured to operate as a server ina data storage and management system.

In an example, a first cluster of nodes such as the nodes 116, 118(e.g., a first set of storage controllers configured to provide accessto a first storage aggregate comprising a first logical grouping of oneor more storage devices) may be located on a first storage site. Asecond cluster of nodes, not illustrated, may be located at a secondstorage site (e.g., a second set of storage controllers configured toprovide access to a second storage aggregate comprising a second logicalgrouping of one or more storage devices). The first cluster of nodes andthe second cluster of nodes may be configured according to a disasterrecovery configuration where a surviving cluster of nodes providesswitchover access to storage devices of a disaster cluster of nodes inthe event a disaster occurs at a disaster storage site comprising thedisaster cluster of nodes (e.g., the first cluster of nodes providesclient devices with switchover data access to storage devices of thesecond storage aggregate in the event a disaster occurs at the secondstorage site).

As illustrated in the clustered network environment 100, nodes 116, 118can comprise various functional components that coordinate to providedistributed storage architecture for the cluster. For example, the nodescan comprise network modules 120, 122 and data modules 124, 126. Networkmodules 120, 122 can be configured to allow the nodes 116, 118 (e.g.,network storage controllers) to connect with host devices 108, 110 overthe storage network connections 112, 114, for example, allowing the hostdevices 108, 110 to access data stored in the distributed storagesystem. Further, the network modules 120, 122 can provide connectionswith one or more other components through the cluster fabric 106. Forexample, in FIG. 1, the network module 120 of node 116 can access asecond data storage device 130 by sending a request through the datamodule 126 of node 118.

Data modules 124, 126 can be configured to connect one or more datastorage devices 128, 130, such as disks or arrays of disks, flashmemory, or some other form of data storage, to the nodes 116, 118. Thenodes 116, 118 can be interconnected by the cluster fabric 106, forexample, allowing respective nodes in the cluster to access data on datastorage devices 128, 130 connected to different nodes in the cluster.Often, data modules 124, 126 communicate with the data storage devices128, 130 according to the SAN protocol, such as SCSI or FCP, forexample. Thus, as seen from an operating system on nodes 116, 118, thedata storage devices 128, 130 can appear as locally attached to theoperating system. In this manner, different nodes 116, 118, etc. mayaccess data blocks through the operating system, rather than expresslyrequesting abstract files.

It should be appreciated that, while the clustered network environment100 illustrates an equal number of network and data modules, otherembodiments may comprise a differing number of these modules. Forexample, there may be a plurality of network and data modulesinterconnected in a cluster that does not have a one-to-onecorrespondence between the network and data modules. That is, differentnodes can have a different number of network and data modules, and thesame node can have a different number of network modules than datamodules.

Further, a host device 108, 110 can be networked with the nodes 116, 118in the cluster, over the storage networking connections 112, 114. As anexample, respective host devices 108, 110 that are networked to acluster may request services (e.g., exchanging of information in theform of data packets) of nodes 116, 118 in the cluster, and the nodes116, 118 can return results of the requested services to the hostdevices 108, 110. In one embodiment, the host devices 108, 110 canexchange information with the network modules 120, 122 residing in thenodes 116, 118 (e.g., network hosts) in the data storage systems 102,104.

In one embodiment, the data storage devices 128, 130 comprise volumes132, which is an implementation of storage of information onto diskdrives or disk arrays or other storage (e.g., flash) as a file-systemfor data, for example. Volumes can span a portion of a disk, acollection of disks, or portions of disks, for example, and typicallydefine an overall logical arrangement of file storage on disk space inthe storage system. In one embodiment a volume can comprise stored dataas one or more files that reside in a hierarchical directory structurewithin the volume.

Volumes are typically configured in formats that may be associated withparticular storage systems, and respective volume formats typicallycomprise features that provide functionality to the volumes, such asproviding an ability for volumes to form clusters. For example, where afirst storage system may utilize a first format for their volumes, asecond storage system may utilize a second format for their volumes.

In the clustered network environment 100, the host devices 108, 110 canutilize the data storage systems 102, 104 to store and retrieve datafrom the volumes 132. In this embodiment, for example, the host device108 can send data packets to the network module 120 in the node 116within data storage system 102. The node 116 can forward the data to thedata storage device 128 using the data module 124, where the datastorage device 128 comprises volume 132A. In this way, in this example,the host device can access the volume 132A, to store and/or retrievedata, using the data storage system 102 connected by the networkconnection 112. Further, in this embodiment, the host device 110 canexchange data with the network module 122 in the node 118 within thedata storage system 104 (e.g., which may be remote from the data storagesystem 102). The node 118 can forward the data to the data storagedevice 130 using the data module 126, thereby accessing volume 1328associated with the data storage device 130.

It may be appreciated that cross-platform replication may be implementedwithin the clustered network environment 100. In an example, the node116 and the node 118 may have different storage platforms, such as wheremerely one of the nodes, such as node 116, has full capabilities ofperforming and managing snapshot replication between the node 116 andthe node 118. Accordingly, a replication destination workflow, a sourcereplication work, and a proxy, representing the node 118, may beimplemented at the node 116 for performing snapshot replicationoperations. It may be appreciated that cross-platform replication may beimplemented for and/or between any type of computing environment, andmay be transferrable between physical devices (e.g., node 116, node 118,a desktop computer, a tablet, a laptop, a wearable device, a mobiledevice, a storage device, a server, etc.) and/or a cloud computingenvironment (e.g., remote to the clustered network environment 100).

FIG. 2 is an illustrative example of a data storage system 200 (e.g.,102, 104 in FIG. 1), providing further detail of an embodiment ofcomponents that may implement one or more of the techniques and/orsystems described herein. The data storage system 200 comprises a node202 (e.g., nodes 116, 118 in FIG. 1), and a data storage device 234(e.g., data storage devices 128, 130 in FIG. 1). The node 202 may be ageneral purpose computer, for example, or some other computing deviceparticularly configured to operate as a storage server. A host device205 (e.g., 108, 110 in FIG. 1) can be connected to the node 202 over anetwork 216, for example, to provide access to files and/or other datastored on the data storage device 234. In an example, the node 202comprises a storage controller that provides client devices, such as thehost device 205, with access to data stored within data storage device234.

The data storage device 234 can comprise mass storage devices, such asdisks 224, 226, 228 of a disk array 218, 220, 222. It will beappreciated that the techniques and systems, described herein, are notlimited by the example embodiment. For example, disks 224, 226, 228 maycomprise any type of mass storage devices, including but not limited tomagnetic disk drives, flash memory, and any other similar media adaptedto store information, including, for example, data (D) and/or parity (P)information.

The node 202 comprises one or more processors 204, a memory 206, anetwork adapter 210, a cluster access adapter 212, and a storage adapter214 interconnected by a system bus 242. The data storage system 200 alsoincludes an operating system 208 installed in the memory 206 of the node202 that can, for example, implement a Redundant Array of Independent(or Inexpensive) Disks (RAID) optimization technique to optimize areconstruction process of data of a failed disk in an array.

The operating system 208 can also manage communications for the datastorage system, and communications between other data storage systemsthat may be in a clustered network, such as attached to a cluster fabric215 (e.g., 106 in FIG. 1). Thus, the node 202, such as a network storagecontroller, can respond to host device requests to manage data on thedata storage device 234 (e.g., or additional clustered devices) inaccordance with these host device requests. The operating system 208 canoften establish one or more file systems on the data storage system 200,where a file system can include software code and data structures thatimplement a persistent hierarchical namespace of files and directories,for example. As an example, when a new data storage device (not shown)is added to a clustered network system, the operating system 208 isinformed where, in an existing directory tree, new files associated withthe new data storage device are to be stored. This is often referred toas “mounting” a file system.

In the example data storage system 200, memory 206 can include storagelocations that are addressable by the processors 204 and adapters 210,212, 214 for storing related software application code and datastructures. The processors 204 and adapters 210, 212, 214 may, forexample, include processing elements and/or logic circuitry configuredto execute the software code and manipulate the data structures. Theoperating system 208, portions of which are typically resident in thememory 206 and executed by the processing elements, functionallyorganizes the storage system by, among other things, invoking storageoperations in support of a file service implemented by the storagesystem. It will be apparent to those skilled in the art that otherprocessing and memory mechanisms, including various computer readablemedia, may be used for storing and/or executing application instructionspertaining to the techniques described herein. For example, theoperating system can also utilize one or more control files (not shown)to aid in the provisioning of virtual machines.

The network adapter 210 includes the mechanical, electrical andsignaling circuitry needed to connect the data storage system 200 to ahost device 205 over a network 216, which may comprise, among otherthings, a point-to-point connection or a shared medium, such as a localarea network. The host device 205 (e.g., 108, 110 of FIG. 1) may be ageneral-purpose computer configured to execute applications. Asdescribed above, the host device 205 may interact with the data storagesystem 200 in accordance with a client/host model of informationdelivery.

The storage adapter 214 cooperates with the operating system 208executing on the node 202 to access information requested by the hostdevice 205 (e.g., access data on a storage device managed by a networkstorage controller). The information may be stored on any type ofattached array of writeable media such as magnetic disk drives, flashmemory, and/or any other similar media adapted to store information. Inthe example data storage system 200, the information can be stored indata blocks on the disks 224, 226, 228. The storage adapter 214 caninclude input/output (I/O) interface circuitry that couples to the disksover an I/O interconnect arrangement, such as a storage area network(SAN) protocol (e.g., Small Computer System Interface (SCSI), iSCSI,hyperSCSI, Fiber Channel Protocol (FCP)). The information is retrievedby the storage adapter 214 and, if necessary, processed by the one ormore processors 204 (or the storage adapter 214 itself) prior to beingforwarded over the system bus 242 to the network adapter 210 (and/or thecluster access adapter 212 if sending to another node in the cluster)where the information is formatted into a data packet and returned tothe host device 205 over the network 216 (and/or returned to anothernode attached to the cluster over the cluster fabric 215).

In one embodiment, storage of information on disk arrays 218, 220, 222can be implemented as one or more storage volumes 230, 232 that arecomprised of a cluster of disks 224, 226, 228 defining an overalllogical arrangement of disk space. The disks 224, 226, 228 that compriseone or more volumes are typically organized as one or more groups ofRAIDs. As an example, volume 230 comprises an aggregate of disk arrays218 and 220, which comprise the cluster of disks 224 and 226.

In one embodiment, to facilitate access to disks 224, 226, 228, theoperating system 208 may implement a file system (e.g., write anywherefile system) that logically organizes the information as a hierarchicalstructure of directories and files on the disks. In this embodiment,respective files may be implemented as a set of disk blocks configuredto store information, whereas directories may be implemented asspecially formatted files in which information about other files anddirectories are stored.

Whatever the underlying physical configuration within this data storagesystem 200, data can be stored as files within physical and/or virtualvolumes, which can be associated with respective volume identifiers,such as file system identifiers (FSIDs), which can be 32-bits in lengthin one example.

A physical volume corresponds to at least a portion of physical storagedevices whose address, addressable space, location, etc. doesn't change,such as at least some of one or more data storage devices 234 (e.g., aRedundant Array of Independent (or Inexpensive) Disks (RAID system)).Typically the location of the physical volume doesn't change in that the(range of) address(es) used to access it generally remains constant.

A virtual volume, in contrast, is stored over an aggregate of disparateportions of different physical storage devices. The virtual volume maybe a collection of different available portions of different physicalstorage device locations, such as some available space from each of thedisks 224, 226, and/or 228. It will be appreciated that since a virtualvolume is not “tied” to any one particular storage device, a virtualvolume can be said to include a layer of abstraction or virtualization,which allows it to be resized and/or flexible in some regards.

Further, a virtual volume can include one or more logical unit numbers(LUNs) 238, directories 236, Qtrees 235, and files 240. Among otherthings, these features, but more particularly LUNS, allow the disparatememory locations within which data is stored to be identified, forexample, and grouped as data storage unit. As such, the LUNs 238 may becharacterized as constituting a virtual disk or drive upon which datawithin the virtual volume is stored within the aggregate. For example,LUNs are often referred to as virtual drives, such that they emulate ahard drive from a general purpose computer, while they actually comprisedata blocks stored in various parts of a volume.

In one embodiment, one or more data storage devices 234 can have one ormore physical ports, wherein each physical port can be assigned a targetaddress (e.g., SCSI target address). To represent respective volumesstored on a data storage device, a target address on the data storagedevice can be used to identify one or more LUNs 238. Thus, for example,when the node 202 connects to a volume 230, 232 through the storageadapter 214, a connection between the node 202 and the one or more LUNs238 underlying the volume is created.

In one embodiment, respective target addresses can identify multipleLUNs, such that a target address can represent multiple volumes. The I/Ointerface, which can be implemented as circuitry and/or software in thestorage adapter 214 or as executable code residing in memory 206 andexecuted by the processors 204, for example, can connect to volume 230by using one or more addresses that identify the one or more LUNs 238.

It may be appreciated that cross-platform replication may be implementedfor the data storage system 200. In an example, the node 202 maycomprise functionality for performing and managing snapshot replication.A second node, not illustrated, may have a different storage platformthan the node 202, and thus may not have full capabilities of performingand managing snapshot replication. Accordingly, a replicationdestination workflow, a source replication work, and a proxy,representing the second node, may be implemented at the node 202 forperforming snapshot replication operations. It may be appreciated thatinline deduplication may be implemented for and/or between any type ofcomputing environment, and may be transferrable between physical devices(e.g., node 202, host device 205, a desktop computer, a tablet, alaptop, a wearable device, a mobile device, a storage device, a server,etc.) and/or a cloud computing environment (e.g., remote to the node 202and/or the host device 205).

One embodiment of cross-platform replication is illustrated by anexemplary method 300 of FIG. 3. At 302, a replication relationship maybe established between a first storage endpoint (e.g., a first storagecontroller hosting first storage that is used as a replication sourcefor replication) and a second storage endpoint (e.g., a second storagecontroller hosting second storage that is used as a replicationdestination for the replication). In an example, the replicationrelationship may correspond to snapshot replication, where a baselinetransfer is performed using a baseline snapshot to transfer data for thefirst time from the first storage to the second storage and/or whereincremental transfers are performed to transfer a delta (e.g., adifference in data, files, directories, a volume, etc.) of the firststorage as captured by a latest snapshot of the first storage and a lastsnapshot of the first storage used to replicate data from the firststorage to the second storage. It may be appreciated that any type ofdata transfer relationship may be established, such as a snapshotreplication relationship, a data migration relationship, a synchronousreplication relationship, an asynchronous replication relationship, asemi-synchronous replication relationship, etc.

The first storage endpoint and the second storage endpoint may bedifferent storage platforms, such as a disk based storage platform, aflash array storage platform, a volume based storage platform, aconsistency group of files and/or LUNs storage platform, a distributedstorage platform such as cloud storage, etc., which may store datadifferently, use different extent sizes, have different compressioncharacteristics, support different types of storage operations andsyntax, have different data and control interfaces, provide differentuser interfaces for administrators, etc. In an example, the firststorage endpoint may have a first storage platform that supportsperforming and managing replication, while the second storage endpointmay lack the ability to fully perform and manage replication (e.g., thesecond storage endpoint may comprise send and/or receive functionality,but not functionality to fully implement all control operationsassociated with replication in the same manner as the first storageplatform). Accordingly, replication source workflow, replicationdestination workflow, and a proxy representing second storage of thesecond storage endpoint may be implemented at the first storage endpointbecause the first storage endpoint is capable of performing and managingthe replication.

At 304, the replication source workflow (e.g., management of controloperations and/or data transfer operations usually performed by a sourcestorage endpoint, such as the first storage endpoint) may be implementedat the first storage endpoint based upon the replication relationship toutilize the first storage, hosted by the first storage endpoint, as thereplication source for replicating data to the second storage hosted bythe second storage endpoint.

At 306, a proxy, representing the second storage of the second storageendpoint, may be implemented at the first storage endpoint. The proxymay be implemented at the first storage endpoint because the secondstorage endpoint may not comprise functionality capable of performingreplication destination workflow. In an example, the first storagecorresponds to a first volume that is natively compatible with thereplication relationship due to the first storage platform being capableof performing and managing the replication, and the second storagecorresponds to a second volume that is not natively compatible with thereplication relationship due to the second storage platform not beingcapable of performing and managing the replication. Accordingly, firstconfiguration data of the first volume may be recorded as a sourcevolume, in the replication relationship, for replication. The proxy(e.g., a virtual proxy volume, a physical proxy volume, or other storageappearing to be natively compatible with the replication relationship)may be recorded as a destination volume, in the replicationrelationship, for replication. In this way, replication destinationworkflow may be implemented upon the proxy (e.g., because the proxyappears to be a destination volume that is natively compatible with thereplication relationship), which may locally execute certain tasks ofthe replication destination workflow (e.g., control operations notnatively supported by the second storage endpoint) or may route certaintasks to the second volume (e.g., file system access operations thatrelate to actual data stored within the second volume). At 308, thereplication destination workflow is implemented, at the first storageendpoint, upon the proxy.

At 310, data sending workflow may be implemented to replicate data fromthe first storage of the first storage endpoint to the second storage ofthe second storage endpoint. For example, a difference between twosnapshots of the first storage may be identified as delta data. The datasending workflow may replicate the delta data to the second storageendpoint to apply to the second storage. In this way, cross-platformreplication may be implemented where not all storage endpoints nativelysupport snapshot replication or other types of replication.

In an example, the first storage endpoint may use a first extent sizetype (e.g., a representation of a LUN may be in 4 kilobyte (KB) blocks)that is different than a second extent size type used by the secondstorage endpoint (e.g., a sequence of variable sized extents).Accordingly, the second storage endpoint may be instructed to maintainan extent bitmap file used to track extent sizes, of the first extentsize type, of data replicated from the first storage endpoint to thesecond storage endpoint. In one example, start-offsets and lengths ofextents being replicated to a first type of storage platform may berecorded within the extent bitmap file. In another example, astart-sector-number and length of extents being replicated to a secondtype of storage platform may be recorded within the extent bitmap file.Each sector can be represented as a bit, such that a start-sector-numberis an offset into the extent bitmap file. A start of an extent can berepresented as a 1 followed by some number of zeroes spanning a lengthof the extent. In this way, when data is restored back from the firststorage endpoint to the second storage endpoint (e.g., responsive todetermining that the first storage endpoint recovered from a failurewhere the second storage endpoint provided clients with access toreplicated data), the second storage endpoint may be instructed toutilize the extent bitmap file to restore data back to the first storageendpoint with extent sizes having the first extent size, which maymitigate space inflation (e.g., a LUN composed of 3 extents of sizes S1,s2, and s3 should be restored back with the same extent I/O sizes of S1,s2, and s3).

In an example, the first storage endpoint may use a first compressionscheme different than a second compression scheme used by the secondstorage endpoint (e.g., compression implemented at a per extent level,compression of 32 KB of data on 32 KB aligned boundaries, etc.).Compression savings may be preserved during replication such as over thewire or on disk at the second storage endpoint. The first storageendpoint and the second storage endpoint may negotiate whether acompression algorithm used by the first storage endpoint isunderstandable or known to the second storage endpoint. If the endpointsboth understand the compression algorithm, then the first storageendpoint will send compressed data over the wire, otherwise the firststorage endpoint will send uncompressed data over the wire. In anexample, the second storage endpoint will either preserve compression ofreplicated data from the first storage endpoint or will decompress andre-compress the replicated data.

In an example, the first storage endpoint may be instructed to performdeduplication upon data that is to be replicated to the second storageendpoint. For example, the first storage endpoint may send names of thedata to the second storage endpoint. If the second storage endpointalready comprises the data, then the first storage endpoint may refrainfrom sending the data. Otherwise, if the second storage endpoint doesnot already comprise the data, then the first storage endpoint may sendthe data to the second storage endpoint.

In an example, the second storage endpoint may be invoked to provideclients with access to replicated data in response to the first storageendpoint incurring a failure. In another example, the second storageendpoint may be capable of creating snapshots of the replicated data. Inanother example, user interfaces for the first storage endpoint and thesecond storage endpoint may be provided in a similar manner for similarclient experiences when managing replication across storage platforms.

FIGS. 4A-4D illustrate examples of a system 400 for cross-platformreplication. FIG. 4A illustrates a first storage endpoint 402 havingcommunication capabilities with a second storage endpoint 412 over anetwork 408. A replication relationship 410 may be established betweenthe first storage endpoint 402 as a replication source and the secondstorage endpoint 412 as a replication destination. For example, thereplication relationship 410 may specify that data of source storage 404of the first storage endpoint 402 (e.g., a LUN, a file, a consistencygroup of LUNs or files, a volume, a directory, etc.) is to be replicatedto destination storage 414 of the second storage endpoint 412, such asby performing baseline and/or incremental transfers using snapshots. Inan example, the first storage endpoint 402 may have a first storageplatform that can perform and/or manage snapshot replication. However,the second storage endpoint 412 may have a second storage platform thatcannot fully perform and/or manage snapshot replication (e.g., in thesame manner as the first storage platform). Accordingly, a proxy 406 maybe implemented at the first storage endpoint 402 to represent thedestination storage 414 of the second storage endpoint 412. For example,the proxy 406 may be a virtual or physical proxy volume that iscompatible with replication functionality provided by the first storageendpoint 402, but is configured to appear to be destination storage ofthe replication.

FIG. 4B illustrates the first storage endpoint 402 implementingreplication source workflow 420 to perform operations that thereplication source is to execute in order to perform and/or managereplication. The first storage endpoint 402 may implement replicationdestination workflow 422 to perform operations that the replicationdestination is to execute in order to perform and/or manage replication(e.g., in place of the second storage endpoint 412 implementing thereplication destination workflow 422 because the second storage endpoint412 may not comprise functionality to adequately perform and/or managereplication with the first storage endpoint 402, thus allowing thesecond storage endpoint 412 to be a lightweight endpoint). In anexample, the replication destination workflow 422 may execute 426 afirst task 424, having a first task type, against the proxy 406 (e.g., acreate stream task may be fully implemented by the proxy 406 withoutbeing routed to the second storage endpoint 412, management of areplication state machine, etc.). The first task type may correspond tocontrol operations that can be locally executed by the proxy 406 withoutaccessing data stored within the destination storage 414.

FIG. 4C illustrates the replication destination workflow 422implementing a second task 430 upon the proxy 406, which is routed 432by the proxy 406 to the second storage endpoint 412 as a routed secondtask 434. The proxy 406 may route 432 the second task 430 because thesecond task 430 may correspond to data within the destination storage414 (e.g., the second task 430 has a second task type that uses datawithin the destination storage 414). For example, the second task 430may comprise a file system access operation. In this way, the proxy 406either executes tasks or routes tasks to the second storage endpoint 412for execution. FIG. 4D illustrates the first storage endpoint 402performing a data transfer 440 from the source storage 404 to thedestination storage 414. For example, the data transfer 440 may send adelta of the source storage 404 between a current snapshot of the sourcestorage 404 and a last snapshot of the source storage 404 used for alast data transfer. In this way, a replication operation may beperformed to replicate data of the source storage 404 to the destinationstorage 414.

One embodiment of cross-platform replication is illustrated by anexemplary method 500 of FIG. 5. At 502, a replication relationship maybe established between a first storage endpoint (e.g., a first storagecontroller hosting first storage that is used as a replication sourcefor replication) and a second storage endpoint (e.g., a second storagecontroller hosting second storage that is used as a replicationdestination for the replication).

The first storage endpoint and the second storage endpoint may bedifferent storage platforms, such as a disk based storage platform, aflash array storage platform, a volume based storage platform, aconsistency group of files and/or LUNs storage platform, a distributedstorage platform such as cloud storage, etc., which may store datadifferently, use different extent sizes, have different compressioncharacteristics, support different types of storage operations andsyntax, have different data and control interfaces, provide differentuser interfaces for administrators, etc. In an example, the secondstorage endpoint may have a second storage platform that supportsperforming and managing replication, while the first storage endpointmay lack the ability to fully perform and manage replication (e.g., thefirst storage endpoint may comprise send and/or receive functionality,but not functionality to fully implement all control operationsassociated with replication in the same manner as the second storageplatform). Accordingly, replication source workflow, replicationdestination workflow, and a proxy representing first storage of thefirst storage endpoint may be implemented at the second storage endpointbecause the second storage endpoint is capable of performing andmanaging the replication.

At 504, a replication destination workflow (e.g., management of controloperations and/or data transfer operations usually performed by adestination storage endpoint, such as the second storage endpoint) maybe implemented at the second storage endpoint based upon the replicationrelationship to utilize second storage, hosted by the second storageendpoint, as a replication destination for storing replicated data fromfirst storage of the first storage endpoint.

At 506, a proxy, representing the first storage of the first storageendpoint, may be implemented at the second storage endpoint. The proxymay be implemented at the second storage endpoint because the firststorage endpoint may not comprise functionality capable of performingreplication source workflow. In an example, the second storagecorresponds to a second volume that is natively compatible with thereplication relationship due to the second storage platform beingcapable of performing and managing the replication, and the firststorage corresponds to a first volume that is not natively compatiblewith the replication relationship due to the first storage platform notbeing capable of performing and managing the replication. Accordingly,second configuration data of the second volume may be recorded as adestination volume, in the replication relationship, for replication.The proxy (e.g., a virtual proxy volume, a physical proxy volume, orother storage appearing to be natively compatible with the replicationrelationship) may be recorded as a source volume, in the replicationrelationship, for replication. In this way, replication source workflowmay be implemented upon the proxy (e.g., because the proxy appears to benatively compatible with the replication relationship), which maylocally execute certain tasks of the replication source workflow (e.g.,control operations not natively supported by the first storage endpoint)or may route certain tasks to the first volume (e.g., file system accessoperations that relate to actual data stored within the first volume).At 508, the replication source workflow is implemented, at the secondstorage endpoint, upon the proxy.

At 510, data sending workflow may be implemented to replicate data fromthe first storage of the first storage endpoint to the second storage ofthe second storage endpoint. For example, a difference between twosnapshots of the first storage may be identified as delta data. The datasending workflow may replicate delta data to the second storage endpointto apply to the second storage. In this way, cross-platform replicationmay be implemented where not all storage endpoints natively supportsnapshot replication or other types of replication.

FIGS. 6A-6D illustrate examples of a system 600 for cross-platformreplication. FIG. 6A illustrates a first storage endpoint 602 havingcommunication capabilities with a second storage endpoint 612 over anetwork 608. A replication relationship 610 may be established betweenthe first storage endpoint 602 as a replication source and the secondstorage endpoint 612 as a replication destination. For example, thereplication relationship 610 may specify that data of source storage 604of the first storage endpoint 602 (e.g., a LUN, a file, a consistencygroup of LUNs or files, a volume, a directory, etc.) is to be replicatedto destination storage 614 of the second storage endpoint 612. In anexample, the second storage endpoint 612 may have a second storageplatform that can perform and/or manage replication. However, the firststorage endpoint 602 may have a first storage platform that cannot fullyperform and/or manage snapshot replication (e.g., in the same manner asthe second storage platform). Accordingly, a proxy 606 may beimplemented at the second storage endpoint 612 to represent the sourcestorage 604 of the first storage endpoint 602. For example, the proxy606 may be a virtual or physical proxy volume that is compatible withthe replication provided by the second storage endpoint 612, but isconfigured to appear to be source storage of the replication.

FIG. 6B illustrates the second storage endpoint 612 implementingreplication destination workflow 620 to perform operations that thereplication destination is to execute in order to perform and/or managereplication. The second storage endpoint 612 may implement replicationsource workflow 622 to perform operations that the replication source isto execute in order to perform and/or manage replication (e.g., in placeof the first storage endpoint 602 implementing the replication sourceworkflow 622 because the first storage endpoint 602 may not comprisefunctionality to adequately perform and/or manage replication with thesecond storage endpoint 612, thus allowing the first storage endpoint602 to be a lightweight endpoint). In an example, the replication sourceworkflow 622 may execute 626 a first task 624, having a first task type,against the proxy 606 (e.g., a create stream task may be fullyimplemented by the proxy 606 without being routed to the first storageendpoint 602, management of a replication state machine, etc.). Thefirst task type may correspond to control operations that can be locallyexecuted by the proxy 606 without accessing data stored within thesource storage 604.

FIG. 6C illustrates the replication source workflow 622 implementing asecond task 630 upon the proxy 606, which is routed 632 by the proxy 606to the first storage endpoint 602 as a routed second task 634. The proxy606 may route 632 the second task 630 because the second task 630 maycorrespond to data within the source storage 604 (e.g., the second task630 may have a second task type that uses data from the source storage604). For example, the second task 630 may comprise a file system accessoperation. In this way, the proxy 606 either executes tasks or routestasks to the first storage endpoint 602 for execution. FIG. 6Dillustrates the first storage endpoint 602 performing a data transfer640 from the source storage 604 to the destination storage 614. Forexample, the data transfer 640 may send a delta of the source storage604 between a current snapshot of the source storage 604 and a lastsnapshot of the source storage 604 used for a last data transfer. Inthis way, a replication operation may be performed to replicate data ofthe source storage 604 to the destination storage 614.

One embodiment of cross-platform replication is illustrated by anexemplary method 700 of FIG. 7. At 702, a replication relationship maybe established between a first storage endpoint (e.g., a first storagecontroller hosting first storage that is used as a replication sourcefor replication) and a second storage endpoint (e.g., a second storagecontroller hosting second storage that is used as a replicationdestination for the replication), such as by a storage server.

The first storage endpoint and the second storage endpoint may bedifferent storage platforms, such as a disk based storage platform, aflash array storage platform, a volume based storage platform, aconsistency group of files and/or LUNs storage platform, a distributedstorage platform such as cloud storage, etc., which may store datadifferently, use different extent sizes, have different compressioncharacteristics, support different types of storage operations andsyntax, have different interfaces, provide different user interfaces foradministrators, etc. In an example, the first storage endpoint and thesecond storage endpoint may not have the ability to perform and/ormanage replication or may perform and/or manage snapshot replication innon-compatible ways. However, the storage server may support performingand managing replication.

Accordingly, a first proxy, representing the first storage endpoint(e.g., representing source storage of the first storage endpoint), maybe implemented at the storage server, at 704. The first proxy may beimplemented at the storage server because the first storage endpoint maynot comprise functionality capable of performing replication sourceworkflow. The first proxy (e.g., a virtual proxy volume, a physicalproxy volume, or other storage appearing to be natively compatible withthe replication relationship) may be recorded as a source volume, in thereplication relationship, for replication. In this way, replicationsource workflow may be implemented upon the first proxy (e.g., becausethe first proxy appears to be natively compatible with the replicationrelationship), which may locally execute certain tasks of thereplication source workflow (e.g., control operations not nativelysupported by the first storage endpoint) or may route certain tasks tofirst storage of the first storage endpoint that comprises the data forreplication (e.g., file system access operations that relate to actualdata stored within the first storage).

A second proxy, representing the second storage endpoint (e.g.,representing destination storage of the second storage endpoint), may beimplemented at the storage server, at 706. The second proxy may beimplemented at the storage server because the second storage endpointmay not comprise functionality capable of performing replicationdestination workflow. The second proxy (e.g., a virtual proxy volume, aphysical proxy volume, or other storage appearing to be nativelycompatible with the replication relationship) may be recorded as adestination volume, in the replication relationship, for replication. Inthis way, replication destination workflow may be implemented upon thesecond proxy (e.g., because the second proxy appears to be nativelycompatible with the replication relationship), which may locally executecertain tasks of the replication destination workflow (e.g., controloperations not natively supported by the second storage endpoint) or mayroute certain tasks to second storage of the second storage endpointinto which replicated data is to be stored (e.g., file system accessoperations that relate to actual data stored within the second storage).

A replication operation, to replicate data from the first storageendpoint (e.g., from the first storage) to the second storage endpoint(e.g., into the second storage) may be performed based upon thereplication relationship. The replication operation may comprise one ormore tasks associated with the replication source workflow and/or thereplication destination workflow. At 708, responsive to a first task ofthe replication operation targeting the first storage endpoint (e.g., atask of the replication source workflow), the first task may beimplemented upon the first proxy. In this way, the first proxy mayeither locally execute the first task or route the first task to thefirst storage endpoint for execution upon the first storage. At 710,responsive to a second task of the replication operation targeting thesecond storage endpoint (e.g., a task of the replication destinationworkflow), the second task may be implemented upon the second proxy. Inthis way, the second proxy may either locally execute the second task orroute the second task to the second storage endpoint for execution uponthe second storage. In this way, the replication operation may beperformed and managed by the storage server.

FIGS. 8A-8D illustrate examples of a system 800 for cross-platformreplication. FIG. 8A illustrates a storage server 802, a first storageendpoint 812, and a second storage endpoint 814 having communicationcapabilities over a network 808. A replication relationship 810 may beestablished between the first storage endpoint 812 as a replicationsource and the second storage endpoint 814 as a replication destination.For example, the replication relationship 810 may specify that data ofsource storage 816 of the first storage endpoint 812 (e.g., a LUN, afile, a consistency group of LUNs or files, a volume, a directory, etc.)is to be replicated to destination storage 818 of the second storageendpoint 814, such as by performing baseline and/or incrementaltransfers using snapshots.

The first storage endpoint 812 and the second storage endpoint 814 maybe different storage platforms, such as a disk based storage platform, aflash array storage platform, a volume based storage platform, aconsistency group of files and/or LUNs storage platform, a distributedstorage platform such as cloud storage, etc., which may store datadifferently, use different extent sizes, have different compressioncharacteristics, support different types of storage operations andsyntax, have different interfaces, provide different user interfaces foradministrators, etc. In an example, the first storage endpoint 812 andthe second storage endpoint 814 may not have the ability to performand/or manage snapshot replication or may perform and/or manage snapshotreplication in non-compatible ways. However, the storage server 802 maysupport performing and managing snapshot replication.

Accordingly, a first proxy 804, representing the first storage endpoint812 (e.g., representing the source storage 816), may be implemented atthe storage server 802. The first proxy may 804 be implemented at thestorage server 802 because the first storage endpoint 812 may notcomprise functionality capable of performing replication sourceworkflow. The first proxy 804 (e.g., a virtual proxy volume, a physicalproxy volume, or other storage appearing to be natively compatible withthe replication relationship 810) may be recorded as a source volume, inthe replication relationship 810, for replication. In this way,replication source workflow may be implemented upon the first proxy 804(e.g., because the first proxy 804 appears to be natively compatiblewith the replication relationship 810), which may locally executecertain tasks of the replication source workflow (e.g., controloperations not natively supported by the first storage endpoint 812) ormay route certain tasks to the source storage 816 of the first storageendpoint 812 that comprises the data for replication (e.g., file systemaccess operations that relate to actual data stored within the sourcestorage 816).

A second proxy 806, representing the second storage endpoint 814 (e.g.,representing the destination storage 818), may be implemented at thestorage server 802. The second proxy 806 may be implemented at thestorage server 802 because the second storage endpoint 814 may notcomprise functionality capable of performing replication destinationworkflow. The second proxy 806 (e.g., a virtual proxy volume, a physicalproxy volume, or other storage appearing to be natively compatible withthe replication relationship 810) may be recorded as a destinationvolume, in the replication relationship 810, for replication. In thisway, replication destination workflow may be implemented upon the secondproxy 806 (e.g., because the second proxy 806 appears to be nativelycompatible with the replication relationship 810), which may locallyexecute certain tasks of the replication destination workflow (e.g.,control operations not natively supported by the second storage endpoint814) or may route certain tasks to the destination storage 818 intowhich replicated data is to be stored (e.g., file system accessoperations that relate to actual data stored within the destinationstorage 818).

FIG. 8B illustrates the storage server 802 implementing replicationsource workflow 820 to perform operations that the replication source isto execute in order to perform and/or manage replication andimplementing replication destination workflow 822 to perform operationsthat the replication destination is to execute in order to performand/or manage replication. In an example, the replication sourceworkflow 820 may execute 826 a first task 824, having a first task type,against the first proxy 804. The replication destination workflow 822may execute 828 a second task 827, having the first task type, againstthe second proxy 806. The first task type may correspond to tasks thatmay be executed by proxies without accessing actual data of the sourcestorage 816 or destination storage 818.

FIG. 8C illustrates the replication source workflow 820 implementing athird task 830 upon the first proxy 804, which is routed 832 by thefirst proxy 804 to the first storage endpoint 812 as a routed third task838. The first proxy 804 may route 832 the third task 830 because thethird task 830 may correspond to data within the source storage 816. Thereplication destination workflow 822 may implement a fourth task 834upon the second proxy 806, which is routed 836 by the second proxy 806to the second storage endpoint 814 as a routed fourth task 840. Thesecond proxy 806 may route 836 the fourth task 834 because the fourthtask 834 may correspond to data within the destination storage 818.

FIG. 8D illustrates the first storage endpoint 812 performing a datatransfer 850 from the source storage 816 to the destination storage 818.For example, the data transfer 850 may send a delta of the sourcestorage 816 between a current snapshot of the source storage 816 and alast snapshot of the source storage 816 used for a last data transfer.In this way, a replication operation may be performed to replicate dataof the source storage 816 to the destination storage 818.

Still another embodiment involves a computer-readable medium comprisingprocessor-executable instructions configured to implement one or more ofthe techniques presented herein. An example embodiment of acomputer-readable medium or a computer-readable device that is devisedin these ways is illustrated in FIG. 9, wherein the implementation 900comprises a computer-readable medium 908, such as a compactdisc-recordable (CD-R), a digital versatile disc-recordable (DVD-R),flash drive, a platter of a hard disk drive, etc., on which is encodedcomputer-readable data 906. This computer-readable data 906, such asbinary data comprising at least one of a zero or a one, in turncomprises a processor-executable computer instructions 904 configured tooperate according to one or more of the principles set forth herein. Insome embodiments, the processor-executable computer instructions 904 areconfigured to perform a method 902, such as at least some of theexemplary method 300 of FIG. 3, at least some of the exemplary method500 of FIG. 5, and/or at least some of the exemplary method 700 of FIG.7, for example. In some embodiments, the processor-executable computerinstructions 904 are configured to implement a system, such as at leastsome of the exemplary system 400 of FIGS. 4A-4D, at least some of theexemplary system 600 of FIGS. 6A-6D, and/or at least some of theexemplary system 800 of FIGS. 8A-8D for example. Many suchcomputer-readable media are contemplated to operate in accordance withthe techniques presented herein.

It will be appreciated that processes, architectures and/or proceduresdescribed herein can be implemented in hardware, firmware and/orsoftware. It will also be appreciated that the provisions set forthherein may apply to any type of special-purpose computer (e.g., filehost, storage server and/or storage serving appliance) and/orgeneral-purpose computer, including a standalone computer or portionthereof, embodied as or including a storage system. Moreover, theteachings herein can be configured to a variety of storage systemarchitectures including, but not limited to, a network-attached storageenvironment and/or a storage area network and disk assembly directlyattached to a client or host computer. Storage system should thereforebe taken broadly to include such arrangements in addition to anysubsystems configured to perform a storage function and associated withother equipment or systems.

In some embodiments, methods described and/or illustrated in thisdisclosure may be realized in whole or in part on computer-readablemedia. Computer readable media can include processor-executableinstructions configured to implement one or more of the methodspresented herein, and may include any mechanism for storing this datathat can be thereafter read by a computer system. Examples of computerreadable media include (hard) drives (e.g., accessible via networkattached storage (NAS)), Storage Area Networks (SAN), volatile andnon-volatile memory, such as read-only memory (ROM), random-accessmemory (RAM), electrically erasable programmable read-only memory(EEPROM) and/or flash memory, compact disk read only memory (CD-ROM)s,CD-Rs, compact disk re-writeable (CD-RW)s, DVDs, cassettes, magnetictape, magnetic disk storage, optical or non-optical data storage devicesand/or any other medium which can be used to store data.

Although the subject matter has been described in language specific tostructural features or methodological acts, it is to be understood thatthe subject matter defined in the appended claims is not necessarilylimited to the specific features or acts described above. Rather, thespecific features and acts described above are disclosed as exampleforms of implementing at least some of the claims.

Various operations of embodiments are provided herein. The order inwhich some or all of the operations are described should not beconstrued to imply that these operations are necessarily orderdependent. Alternative ordering will be appreciated given the benefit ofthis description. Further, it will be understood that not all operationsare necessarily present in each embodiment provided herein. Also, itwill be understood that not all operations are necessary in someembodiments.

Furthermore, the claimed subject matter is implemented as a method,apparatus, or article of manufacture using standard application orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement the disclosedsubject matter. The term “article of manufacture” as used herein isintended to encompass a computer application accessible from anycomputer-readable device, carrier, or media. Of course, manymodifications may be made to this configuration without departing fromthe scope or spirit of the claimed subject matter.

As used in this application, the terms “component”, “module,” “system”,“interface”, and the like are generally intended to refer to acomputer-related entity, either hardware, a combination of hardware andsoftware, software, or software in execution. For example, a componentincludes a process running on a processor, a processor, an object, anexecutable, a thread of execution, an application, or a computer. By wayof illustration, both an application running on a controller and thecontroller can be a component. One or more components residing within aprocess or thread of execution and a component may be localized on onecomputer or distributed between two or more computers.

Moreover, “exemplary” is used herein to mean serving as an example,instance, illustration, etc., and not necessarily as advantageous. Asused in this application, “or” is intended to mean an inclusive “or”rather than an exclusive “or”. In addition, “a” and “an” as used in thisapplication are generally be construed to mean “one or more” unlessspecified otherwise or clear from context to be directed to a singularform. Also, at least one of A and B and/or the like generally means A orB and/or both A and B. Furthermore, to the extent that “includes”,“having”, “has”, “with”, or variants thereof are used, such terms areintended to be inclusive in a manner similar to the term “comprising”.

Many modifications may be made to the instant disclosure withoutdeparting from the scope or spirit of the claimed subject matter. Unlessspecified otherwise, “first,” “second,” or the like are not intended toimply a temporal aspect, a spatial aspect, an ordering, etc. Rather,such terms are merely used as identifiers, names, etc. for features,elements, items, etc. For example, a first set of information and asecond set of information generally correspond to set of information Aand set of information B or two different or two identical sets ofinformation or the same set of information.

Also, although the disclosure has been shown and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure includes all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure. In addition, while aparticular feature of the disclosure may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.

What is claimed is:
 1. A method comprising: receiving, by a firstendpoint that stores data using a first extent size, first data from asecond endpoint that stores data using a second extent size differentthan the first extent size; maintaining, by the first endpoint, anextent bitmap file to track extent sizes, having the second extent size,of the first data replicated from the second endpoint to the firstendpoint, wherein a start-sector-number of extents of the first data isrecorded within the extent bitmap file; and storing, by the firstendpoint, the first data according to the first extent size.
 2. Themethod of claim 1, comprising: recording start-offsets of extents of thefirst data within the extent bitmap file.
 3. The method of claim 1,comprising: recording lengths of extents of the first data within theextent bitmap file.
 4. The method of claim 1, wherein a start of anextent is represented by a first value followed by a number of instancesof a second value spanning a length of the extent within the extentbitmap file.
 5. The method of claim 1, wherein sectors are representedas bits and the start-sector-number is an offset into the extent bitmapfile.
 6. The method of claim 1, wherein a start of an extent isrepresented by a 1 followed by a number of zeros spanning a length ofthe extent within the extent bitmap file.
 7. The method of claim 1,wherein a start of an extent is represented by a 0 followed by a numberof ones spanning a length of the extent within the extent bitmap file.8. The method of claim 1, comprising: in response to receiving a requestto restore the first data from the first endpoint back to the secondendpoint, utilizing the extent bitmap file to restore the first databack to the second endpoint with extent sizes having the second extentsize.
 9. The method of claim 1, wherein the first endpoint stores thefirst data according to a first compression scheme.
 10. The method ofclaim 9, wherein the second endpoint stores the first data according toa second compression scheme different than the first compression scheme.11. The method of claim 1, wherein the first data is deduplicated by thefirst endpoint.
 12. A non-transitory machine readable medium havingstored thereon instructions for performing a method, which when executedby a machine, causes the machine to: receive, by a first endpoint thatstores data using a first extent size, first data from a second endpointthat stores data using a second extent size different than the firstextent size; maintain, by the first endpoint, an extent bitmap file totrack extent sizes, having the second extent size, of the first datareplicated from the second endpoint to the first endpoint; and store, bythe first endpoint, the first data according to the first extent sizeand a first compression scheme different than a second compressionscheme used by the second endpoint to store the first data.
 13. Thenon-transitory machine readable medium of claim 12, wherein theinstructions cause the machine to: record start-offsets of extents ofthe first data within the extent bitmap file.
 14. The non-transitorymachine readable medium of claim 12, wherein the instructions cause themachine to: record lengths of extents of the first data within theextent bitmap file.
 15. The non-transitory machine readable medium ofclaim 12, wherein the instructions cause the machine to: record astart-sector-number of extents of the first data within the extentbitmap file.
 16. The non-transitory machine readable medium of claim 15,wherein sectors are represented as bits and the start-sector-number isan offset into the extent bitmap file.
 17. The non-transitory machinereadable medium of claim 12, wherein the instructions cause the machineto: in response to receiving a request to restore the first data fromthe first endpoint back to the second endpoint, utilize the extentbitmap file to restore the first data back to the second endpoint withextent sizes having the second extent size.
 18. A computing devicecomprising: a memory containing machine executable code; and a processorcoupled to the memory, the processor configured to execute the machineexecutable code to cause the processor to: receive, by a first endpointthat stores data using a first extent size, first data from a secondendpoint that stores data using a second extent size different than thefirst extent size; maintain, by the first endpoint, an extent bitmapfile to track extent sizes, having the second extent size, of the firstdata replicated from the second endpoint to the first endpoint, whereina start of an extent is represented by either a 1 followed by a numberof zeros spanning a length of the extent within the extent bitmap fileor a 0 followed by a number of ones spanning a length of the extentwithin the extent bitmap file; and store, by the first endpoint, thefirst data according to the first extent size.
 19. The computing deviceof claim 18, wherein the machine executable code causes the processorto: record lengths of extents of the first data within the extent bitmapfile.
 20. The computing device of claim 18, wherein the machineexecutable code causes the processor to: in response to receiving arequest to restore the first data from the first endpoint back to thesecond endpoint, utilize the extent bitmap file to restore the firstdata back to the second endpoint with extent sizes having the secondextent size.